EP2559529A1 - Procédé de réglage de la vitesse d'un dispositif de coupe - Google Patents

Abstract

The method involves transporting stack (10) of printed products (3) consecutively on a conveying component (26) of a feed device (4). A final printed product is detected from stack of the printed products formed in a stacking device. The stack is transported to a cutter (12) using feed device. The actual number of cycles of the cutter is regulated based on detection time of final printed product of stack such that the stack is fed to the cutter within a time window.

Description

The invention relates to a method for controlling the speed of a cutting device, wherein the cutting device comprises a cutting unit for cutting printed products and a feeding device for supplying printed matter to the cutting unit, wherein prior to cutting from the printed products in a stacking device stacks of printed products are formed and wherein the printed products of a to be formed stack on a first conveying element of the feeder are transported sequentially.

Raw bound printed matter such as books, paperbacks, magazines or similar products are trimmed to final size after binding to the three unbound edges. In the industrial production of such products, the machines required for the entire production process are usually linked together serially. Here, first printed sheets fed to a gathering machine and collected by this loose book block. Subsequently, the loose book blocks are transferred to a binding machine, in which the book blocks bound in the spine area and the bound printed products transported by means of conveyor belts, on which the setting process of the adhesive used is carried to a cutting device. After the cutting device further machines, such as stackers, filming machines and tying machines can be arranged.

Even if the speeds of the machines and conveyors are coordinated, an irregular promotion may result, in particular on the conveyor belts between binding machine and cutting device, for example, because faulty printed matter discharged, removed by the operator Belegexemplare and fed again or the printed matter are stowed at deflections. As a result, the printed products, in particular the cutting device, are supplied irregularly.

Such a cutting device with a three-knife cutter is for example in the DE3302946 C2 disclosed. However, such devices have the disadvantage that the achievable number of cycles is significantly lower than the maximum achievable number of cycles of the other machines. However, this disadvantage can be compensated for by feeding the printed products into the cutting unit of the cutting device in stacks. The height of the stack to be cut, or the number of printed products per stack, is thereby generated by one, the cutting unit upstream, so-called investor and the stack is fed through this the cutting unit. The feeder comprises a magazine in which the printed products delivered by the binding machine are stacked and a push-off system which pushes down from the magazine stacks of defined height or a defined number of printed products and transfers them to the cutting unit. In order to avoid overfilling of the magazine, the number of cycles of the three-knife trimmer is set slightly higher than is necessary due to the average performance of the binding machine. This reduces the filling level in the magazine continuously.

To prevent the magazine from becoming empty, the level of the magazine is monitored. With a minimum permissible level, the deportation is interrupted and one or more empty cycles of the cutting unit are introduced until a sufficient fill level is reached again. Alternatively, instead of introducing idle cycles, the cutter may be stopped. Such devices have proven themselves in the processing of thick printed products. For thin printed products, however, an exact separation in the stack is uncertain, which can lead to malfunctions and machine downtime.

To avoid this problem, a counted stack is formed in a further design form of cutting devices in the magazine, which is then pushed into the cutting unit. During insertion, the supply of other printed products must be interrupted. For this purpose, an accumulation conveyor may be provided in front of the magazine of the cutting device. Even with this type of devices, the number of cycles of the cutting unit can be selected slightly higher than the average number of cycles required, thus overfilling the accumulation conveyor is avoided. This can be generated from time to time empty cycles or the cutting unit can be stopped. Through the counting process, accurate stacks can be achieved even with thin print products. However, a disadvantage is the power limitation that results from the accumulation conveyor. Namely, the printed products can not be accelerated fast enough after the jam itself by means of a suction belt. Another disadvantage is that sanding marks on the printed products with sensitive surfaces can occur due to the accumulation conveyor.

In the DE3920557 C2 It is proposed to regulate the number of cycles of the cutting device automatically, depending on the stack magazine of the cutting device per unit time supplied printed products. As a result, a largely trouble-free operation of the cutting device is to be made possible despite the non-uniform product flow. Although this method can be used to minimize the number of idle cycles, but not completely avoid. The method is suitable for cutting devices that are charged at a relatively low speed. A fast product feed may result in a jam in the resumption of feed after an interruption of the product feed because the cutter has only a relatively slow acceleration from stall to production speed.

With one in the EP0887157 a feeding device is to be fed, which ensures a selection of the number of items to be cut even with a discontinuous and extremely fast sequence of supplied printed products. For this purpose, the loading device has a counting magazine with two stacking trays arranged one above the other, which are automatically controlled by the feeding and removal of the printed products. With a slide arranged below the counting magazine, the complete stack of printed products can be fed isochronically to the cutting cell. The controller uses signals from magazine-mounted sensors to detect book blocks, with the first sensor positioned directly in front of the magazine, the second at the bottom of the stack and the third at the feed table. Dependent on the number of copies per stack, the counting magazine is operable in different modes.

The DE10321370 also describes a cutting device with a counting magazine, this is preceded by a shed separation device. This should be processed safely thin products that are conveyed in a scale flow.

The invention has for its object to control the speed of a cutting device such that in irregular supply of printed products, the buffer capacity of the stacking magazine is sufficient in any case, to avoid overfilling. In addition, the printed products should be treated gently on their surfaces.

The inventive object is achieved by a method for controlling the speed of a cutting device, wherein the printed products each detected a stack to be formed and based on a time of detection of a last printed product of each stack to be formed an actual cycle number of the cutting unit is controlled such that the stack the cutting unit is fed within a time window.

Preferably, the stack formed is transported on a second conveying element of the feeder to the cutting unit. In this case, the time window is calculated as the difference between a longest available time and a shortest available time for feeding the stack formed to the second conveyor element.

In a preferred embodiment, the stack formed is transported to the cutting unit with a slide of the second conveyor element, wherein a minimum and a maximum value for an offset time is calculated from the calculated time window and the transport of the stack to the cutting unit takes place after the offset time has elapsed. By calculating the actual number of cycles of the cutting unit and adjusted accordingly, it can be ensured that as continuous as possible adaptation of the cutting unit takes place at the speed of the supplied printed products.

In a preferred embodiment, the actual number of cycles of the cutting mechanism is controlled on the basis of the arrival time of the last printed product of a stack to be formed. In this case, the control of the actual cycle number of the cutting unit can be done by reducing or increasing this actual cycle number compared to a previous cycle number. In case of a very late supply of the last printed product of a stack to be formed, at least one empty cycle of the cutting unit is preferably inserted and the actual cycle number of the cutting unit is increased.

In the preferred embodiment, the speed of the printed products on the first conveying element of the feeding device is adjusted depending on a length of the printed products and independent of the actual cycle number of the cutting unit. In this case, the cutting device printed products can be supplied from an upstream processing machine, wherein a nominal number of cycles of the cutting unit of the cutting device is specified by the processing machine.

Fig. 1

eine schematische Darstellung einer Schneidvorrichtung für das dreiseitige Beschneiden von Druckerzeugnissen,

Fig. 2

ein Diagramm mit den zeitlichen Abläufen bei kontinuierlicher Produktzufuhr,

Fig. 3

ein Diagramm mit den zeitlichen Abläufen bei erhöhter Produktzufuhr,

Fig. 4

ein Diagramm mit den zeitlichen Abläufen bei reduzierter Produktzufuhr und

Fig. 5

ein Diagramm mit den zeitlichen Abläufen bei stark reduzierter Produktzufuhr.

The invention will be explained below with reference to the drawing with reference to embodiments. In the drawing show:

Fig. 1

a schematic representation of a cutting device for the three-sided pruning of printed products,

Fig. 2

a diagram with the time sequences with continuous product supply,

Fig. 3

a diagram with the time courses with increased product supply,

Fig. 4

a diagram with the time courses with reduced product supply and

Fig. 5

a diagram with the time sequences with greatly reduced product supply.

The Fig. 1 shows a cutting device 1, by means of a conveyor 2 printed products 3 in a conveying direction F from an upstream processing machine 33, such as a binding machine for the production of printed products, a Entstapelvorrichtung or a feeder, are supplied. In this case, the printed products 3 need not be fed directly from the processing machine 33, but can be cached, for example, before being fed to the cutting device 1. By the cutting device 1, the printed products 3 are cut to finished size at the three open side edges. The arranged between the processing machine 33 and the cutting device 1 conveyor 2 is formed in the simplest case by successive conveyor belts on which the printed products 3 are conveyed individually and in succession. In particular, in plants with a high production capacity, the conveyor 2 may have additional devices, such as scaling and Abschschungsungsvorrichtungen, Ausschleus- and distribution points, addressing devices and curve elements.

The conveyor 2 feeds the printed products 3 one after the other to a feeding device 4 of the cutting device 1, which has a first conveying element 26 which is presently designed as a belt conveyor and which can be driven by means of a controllable motor M ₁ . The speed of the first conveying element 26 upstream conveyor 2 is selected depending on the length of the printed products 3 and the number of cycles of the processing machine 33 so that the spaces between successive printed products 3 on the conveyor 2 are as low as possible. The frequency of supplied printed products 3 is thereby limited upwards. To ensure the formation of spaces between successive printed products 3 for, for example, optical detection, the speed of the first conveying element 26 is always higher than the speed of the conveyor 2.

By means of the first conveying element 26, the printed products 3 are fed to a stacking device 5, which is formed by a vertical stacking shaft 6 with upper stacking slides 7 and lower stacking slides 8 arranged on two levels. The paired stacking slides 7, 8 are in the direction of a double arrow D between a closed position in which the printed products 3 are retained and an open position in which the printed products 3 are released, displaceable. In order to avoid grinding marks on the lowermost printed product 3, the stacking slides 7, 8 are additionally accelerated vertically downwards during opening. By the stacking device 5, the printed products 3 can be buffered for a certain time. The stacking shaft 6 is bounded below by a second conveying element 9 in the form of an infeed table, are fed to the stack 10 formed by the stacking device 5 from a number of printed products 3 stack from above.

On the second conveyor element 9, the stack 10 are promoted by a likewise displaceable in the direction of the double arrow D back and forth inserter 11 on a cutting table, not shown, a cutting unit 12 of the cutting device 1. Subsequently, the stack 10 is clamped between the cutting table and a press plate, also not shown. In this position, the stack 10 is trimmed by means of a front knife 13 at the front edge and by means of side knives 14 at the two side edges, wherein the cutting sequence can also be reversed. After releasing the press plate, the finished trimmed stack 10 is removed by means of a first conveyor 15 and a subsequent second conveyor 16 in a discharge direction A. As a result, the cutting table is free for receiving the next batch 10 to be trimmed.

Preferably, the slide 11 are driven by a motor M ₂ , front blade 13 and side blade 14 together by a motor M ₃ , the first conveyor 15 by a motor M ₄ and the second conveyor 16 by a motor M ₅ . Another Motor M ₆ forms a main drive of the cutting device 1. The main drive drives all not previously mentioned organs of the cutting device 1, such as alignment on the cutting table, transfer devices, etc. and forms the master drive for the motors M _{1 .... 5}

The motors M ₁₆ are designed as angle-controlled motors, which are connected to corresponding drive controllers A _{1 ... 6} . The drive controllers A _{1... 6} are connected to a control device 17 for exchanging control signals. Alternatively, the drive controllers A _{1... 6 may be designed} as part of the control device 17. Outputs of the control device 17 are connected to not shown actuating means for the upper stacking slide 7 and the lower stacking slide 8 and inputs of the control device 17 with light barriers L _{1 ... 3} and a sensor 24.

The light barrier L ₁ is located at the beginning and the light barrier L ₃ at the end of the first conveying element 26. The light barrier L ₂ is arranged after the light barrier L ₁ , wherein a distance 30 between these two light barriers L ₁ , L ₂ corresponds to at least the length of a printed product 3 in the conveying direction F.

The method will be described in detail below, with reference to the Fig. 2 to Fig. 5 , described. The following examples all relate to the cutting of printed matter 3 in stacks of three copies. However, they are generally valid, with a stack 10 being formed by at least one printed product 3. The processing machine 33 produces with a defined number of cycles T, resulting in a nominal number of cycles T _N of one third of the number of cycles T of the processing machine 33 and one cycle time t _Z for the cutting device 1. In continuous operation of the feeding device 4 of the cutting device 1 to be trimmed printed products 3 are also fed continuously through the conveyor 2.

The light beam, the light barrier L ₂ is cyclically interrupted by the transported printed products 3. This results in a signal with dark phases 18 when the light beam is interrupted and with light phases 19 when no printed product 3 is in the range of the light beam. An associated timing diagram is in Fig. 2 shown above, wherein each formed from a dark phase 18 and a light phase 19 pulses 20 consecutively numbered printed products 3 of the respective stack to be formed 10. The indication in the parenthesis indicates the number of a batch 10 and the subscript number indicates a number of the printed product 3 in the stacking 10. The pulse 20 having the number (n + 1) ₂ is thus the printed product 3 having the number two in the stacking 10 associated with the number (n + 1).

Taking into account the number of printed products 3 per stack 10 and the time between successive pulses 20, the control device 17 calculates an associated actual cycle number T _E or a machine cycle Z _{n of} the cutting device 1 and drives the motor M ₆ by means of the drive controller A ₆ corresponding speed. This results in continuously generated pulses 20 through the light barrier L _2, a likewise continuous running of the cutting device 1 with the actual cycle number T _E , which corresponds to the nominal cycle number T _N. The actual cycle number T _E is limited upwards by a maximum cycle number T _MAX and downwards by a minimum cycle number T _MIN .

The speed of the first conveying element 26 of the feeding device 4 is calculated by the control device 17 on the basis of the control device 17 known length of the printed products 3 in the conveying direction F and the motor M _{1 driven} by the drive controller A ₁ at the required speed, the speed of first conveyor element 26 is limited downwards. As a result, it is achieved on the one hand, wiping the printed products 3 in the feeder 4 sufficiently large gaps are formed and on the other hand, a minimum speed in the (lintel-like) supply of the printed products 3 in the stacking device 5 is not exceeded. For the product tracking of the printed products 3 within the feeding device 4 is on a drive wheel 21 of the first conveying element 26, as in Fig. 1 illustrated, a clock 22 is provided, which is formed of a toothed wheel 23 and connected to the control device 17 sensor 24. Alternatively, an already incorporated in the motor M ₁ rotary encoder can be used for this purpose.

By detecting the printed products 3 with the light barrier L ₂ and a product tracking, the control device 17 at any time able to calculate the position of a printed product 3 on the first conveying element 26 relative to the light barrier L ₂ and a time t _B , which requires a printed product 3 to cover a distance 31 between the light barrier L ₂ and the light barrier L ₃ , or the time until the printed product 3 should arrive at the stacking shaft 6. In addition, the control device 17 can calculate an at least required time t _k , which is required after the detection of a last printed product 3 of the stack to be formed by the light barrier L ₃ until a finished stack 10 has formed on the lower stacking slides 8 and a time t _l , which is available at most, until the lower stacking slide 8 must be opened so that they are ready in time for the formation of a next batch 10. Within a time window 25 formed by the time t ₁ and time t _k , the lower stacking slides 8 must be opened and thus the stack 10 fed to the second conveying element 9 from above.

On the other hand, the slide 11 must be located in a rear end position 27 when the lower stacking slide 8 are opened and may only begin its forward movement when the stack 10 is on the second conveyor element 9. The movement sequence 29 of the slide 11 is in the Fig. 2 to Fig. 5 shown, wherein the slide 11 between its rear end position 27, in which a stack 10 can be supplied from above and a front end position 28, in which the stack has been completely promoted to the cutting table, is displaceable. In its rear end position 27, the slide 11 is stationary during a rest time t _r , wherein the rest time t _r corresponds to a constant portion of a machine cycle Z _n .

The earliest possible time t _f , at which the inserter 11 can begin insertion, is obtained when the stack 10 is supplied from the top at time t _k and has reached the second delivery element 9 immediately after a fall time t _o . The latest possible time t _s , at which the inserter 11 can begin insertion, arises when the stack 10 is supplied at the time t _l from above, at the same time the slide 11 has reached its rear end position 27 and after Expiration of the rest time t _r , during which the inserter 11 remains in the rear end position 27.

An area B within which the inserter 11 may begin with the insertion of a stack 10 is thus calculated according to the formula B = t _l -t _k + t _r -t _o. The control device 17 calculates an offset time t _offset = t _B + t _k + t _o + t _v for each passage of the last printed product 3 of a stack 10 to be formed at the light barrier L ₂ until the beginning of the insertion movement of the inserter 11 (t _v to) selecting advantageous time, see below) and corrects the actual cycle number T _E or the machine cycle Z _{n of} the cutting unit 12 in the sense that the beginning of the insertion movement can take place exactly after the offset time t _offset . It is advantageous if the time t _{v is} chosen to be approximately equal to B / 2 in order to be able to react both to short-term increased or reduced delivery speeds of printed products 3.

On each passage of the last printed product 3 of a stack 10 to be formed at the light barrier L ₃ , the control device 17 compares the calculated time t _B , with a measured and corrected in case of deviation, the actual cycle number T _{E of} the cutting unit 12 in the sense that the beginning of the insertion movement can take place at the intended location within the area B. By means of measuring the time of arrival of the printed products 3 at the stacking shaft 6, it is additionally possible to control the stacking slides 7, 8 more precisely in terms of time.

The process is described with reference to stack 10, consisting of the three printed products 3 with the numbers n ₁ , n ₂ , n ₃ . Printed products 3 with the numbers n ₁ and n ₂ are detected by the light barrier L ₂ and generate the pulses 20 (n ₁ ) and 20 (n ₂ ). If the front edge of the printed product 3 with the number n _{3 reaches} the light barrier L ₂ , the times t ₁ , t _k , t ₀ , t _v t _r and t _{B are} determined. From this, the control device 17 then calculates the offset time t _Offset . Some of the values for the times t ₁ , t _k , t _o , t _v , t _r and t _B may alternatively be stored as a constant in a memory of the control device 17 and read out from here. The value for t _o can be classified as constant, for example, if the fall time t _o a stack 10 in one and the same stacking device 5 constructively always has the same value.

If the calculation shows that when the cutting unit 12 of the cutting device 1 continues to run at the instantaneous actual cycle number T _E , after the time t _{offset of} the inserters 11 has elapsed, the actual cycle number T _E will remain constant. Otherwise, the actual cycle number T _{E is} adapted, as will be explained in more detail in the further description.

Fig. 3 shows the case in which the three printed products 3 arrive with the numbers n _{1 ... 3} with increased cadence and thus arrives earlier, the third, or last printed product 3 with the number n ₃ to be formed, the number n bearing stack 10 than at a previous machine cycle Z ( _n-2 ). By means of the control device 17, the actual cycle number T _{E is} increased so far that the slide 11 is then ready to insert the next stack 10 with the number n after the time t _offset isochronous. As a result, the machine cycle Z _(n-1) for the stack 10 having the number (n-1 _{) is} shortened with respect to the machine cycle Z _(n-2) .

Fig. 4 shows the case in which the three printed products 3 arrive with the numbers n _{1 ... 3} with reduced cadence and thus arrives later, the third, or last printed product 3 with the number n ₃ to be formed, the number n carrying stack 10 later than the previous machine cycle Z _(n-2) . By means of the control device 17, the actual cycle number T _{E is} reduced so much that the slide 11 is then ready in time to insert the next stack 10 with the number n isochromatically after the time t _offset . As a result, the machine cycle Z _(n-1) for the stack 10 having the number (n-1 _{) is} lengthened from the machine cycle Z _(n-2) . If it is not possible, by increasing or decreasing the actual cycle number T _E , to compensate for the too early or late arrival time of the last printed product 3 of a stack 10 to be formed, the cutting unit 12 will be moved over several machine cycles with increased or decreased actual Number of cycles T _E driven. In the processing of stacks 10, which have a large number of printed products 3, it is conceivable that the last printed product 3 preceding Print products 3 to detect a stack 10 to be detected by the light barrier L ₂ and by evaluating this signal already the actual cycle number T _E to control.

In the Fig. 5 a case is shown in which the third, or last printed product 3 with the number n _{3 of} the stack 10 is detected so far belated by the light barrier L ₂ that the calculated actual cycle number T _E would have to be lower than the minimum number of cycles T _MIN , which is not possible. In this case, the actual cycle number T _{E is} increased and the slide 11 retained during at least one machine cycle Z in its rear end position 27, whereby the cutter 12 performs at least one so-called empty cycle in a machine cycle Z _empty . In an idle cycle, the slide 11 remains in its rear end position 27 and the motor M ₃ for driving the front blade 13 and the side blade 14 is then stopped for the duration of a machine cycle. If there are no more printed products 3 within the cutting unit 12 after several consecutive empty cycles, all drives of the cutting unit 12 can be stopped. The actual cycle number T _E is calculated so that after expiration of t _offset the slide 11 begins with the Abschiebebewegung. In the present example, this is not possible because the actual cycle number T _E would be greater than T _MAX and thus limited to T _MAX . This has the consequence that in comparison to the previously described processes, the time t _v by a control deviation R is greater. For a so-called "normal case", as in the Fig.1 to Fig.4 shown, the control deviation R has the value "0". After the detection of the printed product 3 with the number (n + 1) ₃ through the light barrier L ₂ , the actual cycle number T _{E is} recalculated, in the sense that after the expiration of t _offset the slide 11 begins with the insertion. From the machine cycle Z _{(n + 1)} , the value of the time t _{v is} back to the intended value and the cutting device 1 can continue to produce with a constant actual cycle number T _E = T _N.

The method can be simplified as a synchronization method of the cutting unit 12 of a cutting device 1 by previously detecting the printed products 3 and controlling the actual number of cycles of the cutting unit 12 according to the supplied printed products 3, wherein in the case that the stack to be cut 10th is formed too late, the actual cycle number T _{E of} the cutting unit 12 is increased and at least one empty cycle is generated. By means of the light barrier L ₁ and the light barrier L ₂ together with the clock 22, the control device 17 is able to determine whether and where a printed product 3 is located on the first conveyor element 26. This makes it possible, in the case of a stop of the cutting device 1 and / or the conveyor 2, to empty the first conveying element 26 at the original speed or to stop it so fast that the stacking device 5 is supplied with no printed product 3 at too low a speed. If, after stopping the first conveying element 26, there is still a printed product 3 on the first conveying element 26, the first conveying element 26 can be driven backwards until printed product 3 is detected by the light barrier L ₁ .

After restarting the first conveying element 26 in the conveying direction F, there is then a large acceleration path available to the printed product 3 thereon, so that the (lint-like) feeding into the stacking device 5 can take place at full speed.

Claims (8)

Method for controlling the speed of a cutting device (1), wherein the cutting device (1) has a cutting unit (12) for cutting printed products (3) and a feeding device (4) for feeding printed products (3) to the cutting unit (12) Cutting from the printed products (3) in a stacking device (5) Stacks (10) of printed products (3) are formed and wherein the printed products (3) of a stack to be formed (10) on a first conveying element (26) of the feeding device (4) be transported in succession, characterized in that the printed products (3) each detected a stack to be formed (10) and based on a time of detection of a last printed product (3) of each stack to be formed (10) an actual cycle number (T _E ) of the cutting unit (12) is controlled such that the stack (10) is supplied to the cutting unit (12) within a time window (25). Method according to Claim 1, characterized in that the stack (10) formed is transported on a second conveying element (9) of the feeding device (4) to the cutting unit (12) and the time window (25) is calculated as the difference between a longest available time ( t _l ) and a shortest available time (t _k ) for feeding the formed stack (10) to the second conveyor element (9) is calculated. Method according to claim 2, characterized in that the formed stack (10) is transported to the cutting unit (12) with a slide (11) of the second conveying element (9), whereby a minimum and a maximum value for an offset time ( t _offset ) is calculated, and wherein the transport of the stack (10) to the cutting unit (12) after expiration of the offset time (t _offset ) takes place. Method according to one of claims 1 to 3, characterized in that the actual number of cycles (T _E ) of the cutting unit (12) due to the arrival time the last printed product (3) of a stack (10) to be formed is regulated. Method according to one of claims 1 to 4, characterized in that the control of the actual number of cycles (T _E ) of the cutting unit (12) by reducing or increasing this actual number of cycles over a previous number of cycles takes place. Method according to one of claims 1 to 5, characterized in that at a very late supply of the last printed product (3) of a stack to be formed (10) at least one blank cycle of the cutter (12) inserted and the actual cycle number (T _E ) of the cutting unit (12) is increased. Method according to one of claims 1 to 6, characterized in that the speed of the printed products (3) on the first conveying element (26) of the feeding device (4) depends on a length of the printed products (3) and independent of the actual cycle number (T _E ) of the cutting unit (12) is set. Method according to one of claims 1 to 7, characterized in that the cutting device (1) printed products (3) from an upstream processing machine (33) are fed, wherein a nominal number of cycles (TN) of the cutting unit (12) of the cutting device (1) of the processing machine (33) is specified.

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